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This invention relates to security systems, and more particularly to a dome housing assembly including a panning and tilting mechanism for a video camera.
It is well known to employ video cameras in locations, such as banks, casinos, and retail stores to monitor security. Video cameras are also employed outdoors to monitor parking lots, traffic, and weather conditions.
To make them inconspicuous and protect them from tampering and the environment, such video cameras are typically mounted in dome housings that include relatively large, high torque, motors for panning and tilting the cameras. The panning and tilting mechanisms often employ reduction gears, linkages, and drive belts to couple the drive motors to the cameras. Such mechanisms typically result in a relatively large, 15 to 31 centimeter (6 to 12 inch), diameter, high profile dome housing that is subject to vibrations and reliability problems. Of course, such a housing is unduly conspicuous and has limited applicability where space is limited.
In outdoor applications, video cameras are subject to widely varying environmental conditions that subject them to problems, such as dome fogging. Accordingly, prior dome camera housings have employed xe2x80x9cdefrostingxe2x80x9d heaters. All of these considerations lead to a dome housing and video camera assembly that is unduly large, complex, and costly.
What is still needed, therefore, is a dome housing and video camera assembly that overcomes these problems.
An object of this invention is, therefore, to provide a video camera housing having a significantly smaller size and profile.
Another object of this invention is to provide a video camera housing having a compact, simple, and reliable camera panning and tilting mechanism.
Yet another object of this invention is to provide a video camera housing that is rugged, suitable for use outdoors, and is significantly less costly cost to manufacture.
A rugged, miniature pan/tilt dome camera assembly of this invention includes a base housing and a transparent dome that is attached to the base housing by a dome mounting flange. The base housing holds internal components including a pan motor, a tilt motor, and a video camera, all of which are mounted to a movable platform that is suspended by horizontal and vertical bearings to a platform support ring that is attached to the base housing.
The drive shaft of the pan motor is direct-coupled to the platform support ring by a panning drive wheel that includes a compliant xe2x80x9ctirexe2x80x9d for providing friction between to the platform support ring. The bearings suspending the movable platform to the platform support ring apply continuous pressure for driving friction between the panning drive wheel and the platform support ring when panning the video camera through azimuthal angles.
The tilt motor is attached to the movable platform and its drive shaft is directly coupled to the video camera for tilting the camera up and down through a range of elevation angles. Unlike prior dome camera assemblies, the pan and tilt motors are both mounted on the movable platform rather than one or both being mounted to the base housing. Moreover, the pan and tilt motors are mounted in a balanced configuration on the movable platform at opposite sides of the video camera. The drive shafts of the pan and tilt motors preferably rotate about a common axis that extends through the center of gravity of the video camera. The pan and tilt motors directly drive the movable platform and the video camera without gears, belts, pulleys, or the like, which reduces parts costs, size requirements, and improves reliability. Moreover, the balanced mounting configuration allows a reduced height for the base housing and reduces the motor torque requirements, thereby improving camera positioning speed and accuracy.
Additional aspects and advantages of this invention will be apparent from the following detailed description of preferred embodiments thereof, which proceed with reference to the accompanying drawings.